Groundwater nitrate problem and countermeasures in strongly affected EU countries—a comparison between Germany, Denmark and Ireland

Water resources protection co-occurring with intensive agriculture brings major challenges in Europe including groundwater contamination with nitrate (NO₃⁻). Due to non-compliance with the EU Nitrates Directive, some intensively agricultural member states have been penalized by European jurisdiction, putting them under great pressure to reduce groundwater NO₃⁻ concentrations. This review summarizes the situation of groundwater NO₃⁻ pollution in Germany, Denmark and Ireland, critically compares the measures taken to improve it, and identifies potentials for improvement and mutual learning. Denmark is often considered a leader in the field with the NO₃⁻ countermeasures program being continuously developed since 1985. However, impacts on agriculture productivity and crop quality are evident. Ireland also considers NO₃⁻ one of the most serious water quality problems, but differs in hydrogeological setting and drinking water management. Climate change is expected to massively aggravate challenges to all affected countries by causing scarcity of water resources and increasing the pressure on water quality.